342 



THE WINGS OF LEPIDOPTERA 



The anastomosis of veins. — In many genera of this order the branches 

 of radius of the fore wings anastomose so as to form one or more closed cells; 

 these have been termed the accessory cells. 



Sc+R, 



Fig. 352. — Base of a hind wing of a pupa of Anosia. 



By an application of the uniform terminology, the homology of the 

 accessory cells can be indicated. Thus in Prionoxystus (Fig. 343), where 



veins R3 and R4+5 anastomose, 

 cell R3 is divided into two 

 parts, and the accessory cell 

 is evidently ist cell R3. 



The costa of the hind 

 wings. — Except at the base of 

 the wing in certain members of 

 this order, the costal margin of 

 the hind wings is not thickened 

 appreciably; it may be said, 

 therefore, that the costal vein 

 is either very greatly reduced 

 in length or is lost entirely in 

 the hind wings of the Lepidop- 

 tera. In the hind wings of 

 some pupae, as that of the 

 monarch butterfly, for ex- 

 ample, there is a distinct 

 costal trachea (Fig. 352); but 



3<-^^ 2d A ^stA 



Fig- 353- — Wings of Caccecia cerasivorana. 



in the hind wing of the adult of this species there is no indication of a 

 costal vein. 



